The invention relates to a device to be used for the measurement of the maximum, or peak, rate of urine flow from human subjects, for clinical analytical purposes. Such a measurement is useful as a standard clinical indicator of urodynamic obstruction. The invention could also be adapted as a low cost tool for the gauging of peak fluid flow in other medical and industrial applications.
A constriction or obstruction of the urethra reduces the flow rate of urine. Prostatic hyperplasia is one example of a condition common in males. Urethra damage resulting from trauma is also common, particularly in the case of road accident victims. In general, a peak urine flow rate in excess of 15 milliliters per second is considered normal for a man. A peak flow rate of less than 10 milliliters per second, has a high probability of being associated with an urodynamic obstruction. A measure of peak flow rate therefore provides a useful diagnostic indicator to a physician. Furthermore, the efficacy of treatments for the condition, through surgery, or pharmacological means, may be objectively assessed by measuring urine peak flow rate.
It is desirable to offer a means of peak urine flow measurement that is low cost, does not require the presence of expert staff, and that can preferably be used, unaided, by the patient.
There is a considerable body of prior art in the field. Current use is made of bulky and expensive electronic equipment that measures the peak flow with considerable accuracy, and is often combined with apparatus for retaining the urine sample to allow for laboratory analysis of the urine. Such apparatus requires specially trained staff to operate it, who are required to be present while the urine sample is being provided by the patient. This encroachment on the patient's privacy can interfere with the accuracy of the test result obtained. Other prior art, such as that described in U.S. Pat. No. 4,753,249 represents a variation of a multi-orifice design based on the urinometer of Willard Drake, and as described in his 1953 patent U.S. Pat. No. 2,648,981. By its use of a simple measurement vessel and orifice, the current invention offers a design of significantly reduced complexity and ease of manufacture, appropriate to the rapid screening of patients suffering urodynamic conditions and without recourse to expert assistance.